[PATCH] x86_64: check if ptrace RIP is canonical

This works around an AMD Erratum.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Chris Wright <chrisw@osdl.org>

diff --git a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c
index eaa7250152f56ca7f55e94dc42ca61f8ad9488b5..b2b7e347a6715f7f487928336608a411564e7e5f 100644 (file)
--- a/arch/x86_64/kernel/ptrace.c
+++ b/arch/x86_64/kernel/ptrace.c
@@ -149,6 +149,11 @@ static int putreg(struct task_struct *child,
                                return -EIO;
                        value &= 0xffff;
                        break;
+               case offsetof(struct user_regs_struct, rip):
+                       /* Check if the new RIP address is canonical */
+                       if (value >= TASK_SIZE)
+                               return -EIO;
+                       break;
        }
        put_stack_long(child, regno - sizeof(struct pt_regs), value);
        return 0;